<?php
/*
 *  $Id: Driver.php 7490 2010-03-29 19:53:27Z jwage $
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * This software consists of voluntary contributions made by many individuals
 * and is licensed under the LGPL. For more information, see
 * <http://www.doctrine-project.org>.
 */

/**
 * Abstract cache driver class
 *
 * @package     Doctrine
 * @subpackage  Cache
 * @license     http://www.opensource.org/licenses/lgpl-license.php LGPL
 * @link        www.doctrine-project.org
 * @since       1.0
 * @version     $Revision: 7490 $
 * @author      Konsta Vesterinen <kvesteri@cc.hut.fi>
 * @author      Jonathan H. Wage <jonwage@gmail.com>
 */
abstract class Doctrine_Cache_Driver implements Doctrine_Cache_Interface
{
	/**
	 * @var array $_options      an array of options
	 */
	protected $_options = array();

	/**
	 * Configure cache driver with an array of options
	 *
	 * @param array $_options      an array of options
	 */
	public function __construct($options = array())
	{
		$this->_options = $options;
	}

	/**
	 * Set option name and value
	 *
	 * @param mixed $option     the option name
	 * @param mixed $value      option value
	 * @return boolean          TRUE on success, FALSE on failure
	 */
	public function setOption($option, $value)
	{
		if (isset($this->_options[$option])) {
			$this->_options[$option] = $value;
			return true;
		}
		return false;
	}

	/**
	 * Get value of option
	 *
	 * @param mixed $option     the option name
	 * @return mixed            option value
	 */
	public function getOption($option)
	{
		if ( ! isset($this->_options[$option])) {
			return null;
		}

		return $this->_options[$option];
	}

	/**
	 * Fetch a cache record from this cache driver instance
	 *
	 * @param string $id cache id
	 * @param boolean $testCacheValidity        if set to false, the cache validity won't be tested
	 * @return mixed  Returns either the cached data or false
	 */
	public function fetch($id, $testCacheValidity = true)
	{
		$key = $this->_getKey($id);
		return $this->_doFetch($key, $testCacheValidity);
	}

	/**
	 * Test if a cache record exists for the passed id
	 *
	 * @param string $id cache id
	 * @return mixed false (a cache is not available) or "last modified" timestamp (int) of the available cache record
	 */
	public function contains($id)
	{
		$key = $this->_getKey($id);
		return $this->_doContains($key);
	}

	/**
	 * Save some string datas into a cache record
	 *
	 * @param string $id        cache id
	 * @param string $data      data to cache
	 * @param int $lifeTime     if != false, set a specific lifetime for this cache record (null => infinite lifeTime)
	 * @return boolean true if no problem
	 */
	public function save($id, $data, $lifeTime = false)
	{
		$key = $this->_getKey($id);
		return $this->_doSave($key, $data, $lifeTime);
	}

	/**
	 * Remove a cache record
	 *
	 * Note: This method accepts wildcards with the * character
	 *
	 * @param string $id cache id
	 * @return boolean true if no problem
	 */
	public function delete($id)
	{
		$key = $this->_getKey($id);

		if (strpos($key, '*') !== false) {
			return $this->deleteByRegex('/' . str_replace('*', '.*', $key) . '/');
		}

		return $this->_doDelete($key);
	}

	/**
	 * Delete cache entries where the key matches a PHP regular expressions
	 *
	 * @param string $regex
	 * @return integer $count The number of deleted cache entries
	 */
	public function deleteByRegex($regex)
	{
		$count = 0;
		$keys = $this->_getCacheKeys();
		if (is_array($keys)) {
			foreach ($keys as $key) {
				if (preg_match($regex, $key)) {
					$count++;
					$this->delete($key);
				}
			}
		}
		return $count;
	}

	/**
	 * Delete cache entries where the key has the passed prefix
	 *
	 * @param string $prefix
	 * @return integer $count The number of deleted cache entries
	 */
	public function deleteByPrefix($prefix)
	{
		$count = 0;
		$keys = $this->_getCacheKeys();
		if (is_array($keys)) {
			foreach ($keys as $key) {
				if (strpos($key, $prefix) === 0) {
					$count++;
					$this->delete($key);
				}
			}
		}
		return $count;
	}

	/**
	 * Delete cache entries where the key has the passed suffix
	 *
	 * @param string $suffix
	 * @return integer $count The number of deleted cache entries
	 */
	public function deleteBySuffix($suffix)
	{
		$count = 0;
		$keys = $this->_getCacheKeys();
		if (is_array($keys)) {
			foreach ($keys as $key) {
				if (substr($key, -1 * strlen($suffix)) == $suffix) {
					$count++;
					$this->delete($key);
				}
			}
		}
		return $count;
	}

	/**
	 * Delete all cache entries from the cache driver
	 *
	 * @return integer $count The number of deleted cache entries
	 */
	public function deleteAll()
	{
		$count = 0;
		if (is_array($keys = $this->_getCacheKeys())) {
			foreach ($keys as $key) {
				$count++;
				$this->delete($key);
			}
		}
		return $count;
	}

	/**
	 * Get the hash key passing its suffix
	 *
	 * @param string $id  The hash key suffix
	 * @return string     Hash key to be used by drivers
	 */
	protected function _getKey($id)
	{
		$prefix = isset($this->_options['prefix']) ? $this->_options['prefix'] : '';

		if ( ! $prefix || strpos($id, $prefix) === 0) {
			return $id;
		} else {
			return $prefix . $id;
		}
	}

	/**
	 * Fetch an array of all keys stored in cache
	 *
	 * @return array Returns the array of cache keys
	 */
	abstract protected function _getCacheKeys();

	/**
	 * Fetch a cache record from this cache driver instance
	 *
	 * @param string $id cache id
	 * @param boolean $testCacheValidity        if set to false, the cache validity won't be tested
	 * @return mixed  Returns either the cached data or false
	 */
	abstract protected function _doFetch($id, $testCacheValidity = true);

	/**
	 * Test if a cache record exists for the passed id
	 *
	 * @param string $id cache id
	 * @return mixed false (a cache is not available) or "last modified" timestamp (int) of the available cache record
	 */
	abstract protected function _doContains($id);

	/**
	 * Save a cache record directly. This method is implemented by the cache
	 * drivers and used in Doctrine_Cache_Driver::save()
	 *
	 * @param string $id        cache id
	 * @param string $data      data to cache
	 * @param int $lifeTime     if != false, set a specific lifetime for this cache record (null => infinite lifeTime)
	 * @return boolean true if no problem
	 */
	abstract protected function _doSave($id, $data, $lifeTime = false);

	/**
	 * Remove a cache record directly. This method is implemented by the cache
	 * drivers and used in Doctrine_Cache_Driver::delete()
	 *
	 * @param string $id cache id
	 * @return boolean true if no problem
	 */
	abstract protected function _doDelete($id);
}